Question: The arithmetic sequence $(a_i)$ is defined by the formula: $a_i = 1 + 5(i - 1)$ What is $a_{9}$, the ninth term in the sequence?
Solution: From the given formula, we can see that the first term of the sequence is $1$ and the common difference is $5$ To find $a_{9}$ , we can simply substitute $i = 9$ into the given formula. Therefore, the ninth term is equal to $a_{9} = 1 + 5 (9 - 1) = 41$.